Double action letoff



I s 6 md %n Z T N 1 fl R E0 u mm 2 z r 0 d. 6% F Hm F.1 05 T9 ow N o Mmnh m Bl Wm D Nov. 25, 1952 Patented Nov. 25, 1952 UNITED STATES PATENFICE 2,619,1ae DQUBLE ACTION ET-DEF Hector Emond, Suncook, N. H.dpplication January 8, 1951, Serial No. 204,905 2 Claims. (01. 39 198)The present invention relates to improvements in let-off mechanisms forlooms, and'mcre particularly to a novel brakingor friction element forcontrolling thelet-off mechanism drive shaft.

One object of the invention is to provide a letoif mechanism of theBartlett type for looms having a friction braking element arrangedbetween the drive worm and ratchet mechanism in addition to theconventional friction element to control the let-off drive shaftuniformly and increase the accuracy of the Iet oIT-mechanism.

Another object is to'pr'o'vide a let-off mechanism for looms with afriction braking element for controlling rotation ofthe drive shaftwhich will enable the shaftft'o be rotated uniformly and evenly by thelay .and ratchet mechanism to thus impart uniform motion to the warpbeam or the cm.

An'other'object is to provide a let-off mechanism for looms with dualbraking elements arranged such as to'balance out vibrations and toafford the let-off mechanism with a nicety of control.

Another object is to provide a let-01f mechanism for looms in which thefriction collars are floatingly mounted with one friction element orbrake mounted above the vdrivelworm on the let-off shaft and the otherfriction element mounted therebelow which will maintain the let-offshaft under a constant drag at both ends of the worm so that one endwill not have a tendency to move within the limits of the bearing playcreating backlash;

Another object is to provide a let-off mechanism which will stop unevenweave caused by irregular motion impartedio the warp-beam during thelet-off stroke or movement when weaving various types of cloth such ascotton and rayon. Thus, the efiiciency of the loom is increased and thefabric weave is enhanced.

Other objects and advantages of the invention will become apparentduring the course of the following description of the accompanyingdrawing, wherein- Figure 1 is a front elevational view of a Bartletttype let-off mechanism showing the friction brake element arrangedbetween the drive worm and ratchet mechanism.

Figure 2 is a side elevational view showing a portion of the loom insection and parts of the let-off mechanism broken away to illustratevarious structural details.

Figure 3 is a top elevational view of the collar or friction brake drumwhich is mounted on the let- 1f drive shaft between the drive worm andratchet mechanism! Figure '4 is a"diame tric al cross-sectional viewtaken'on line 44' of Figure 3 and looking in the direction of thearrowsto illustrate themanner in which the friction drum is secured tothe drive shaft.

Figure .5 is an edge elevational view of the friction'collar retainingbracket which is adapted to be bolted to the lo om'sidewith its endpresented to the friction, collargand j Figure {5' is a" frontelevational view of the same.

In the drawin and mor in detail. attention is first directed "to Figures1 and 2 wherein there is shown for the purpose of convenience ofillustration aloom frame generall'y'des'ig'nated 5'to which is applied aBartlett typelet -off mechanism which is 'provi dedfor controlling the'warp beam in accordance 'with the loom mechanism. The let-01fmechanisrri'being controlled usually from the lay' sword throughsuitable linkage. This type of' letfloff mechanism is employed forplacing the warp'beam under constanttension and is shown iri'U; s:'Pateht2,350,954.

' The let-off mechanism 5 includes a bracket plate 1 which is'affixed'to the loom side by bolts 8 secured in place by nuts 9. A pair ofspaced bracket arms lll and H are integrated withthe bracket plate, andare provided 'on their free ends with bearing collars or :bosses l2 andI3 respectively. Formed integral with the bracket arm 'H is an offsetarm 14 having a downwardly extending portion 15 angularly bent 'at itslower end toform ahorizontal arm .16. The horizontal end [6 terminatesinabearingboss I! in vertical alinementwith the bearing bosses I12 and i3.

' Rotatably mounted in the alined bearing bosses l2; I3 and J! is alet-off drive 'shaftlwto which is affixed the hub 20 of a worm 21; Setscrews 22 are received in correspondingly threaded openings in the hub29 for locking the worm to the shaft. The lower end of the shaft I8 isfitted with a ratchet 24 which has its hub likewise secured to the shaftand rotatably mounted above the ratchet is a ratchet pawl carrier 25 towhich is pivoted a lay control link 26.

The worm 2! is arranged in driving engagement with a worm wheel 21(Fig. 1) which has its hub 28 secured to a drive shaft 29, which driveshaft is provided with a spur gear for drivingly engaging the ring gearon the warp beam (not shown), and the shaft 29 is supported in a bearingboss 3!! integrated with arms 3| and 32, the

3 other ends of which are integrated with the bearing bosses l2 and 13respectively.

The upper end of the shaft [8 is provided with a hand wheel 33 having agrooved hub 34 surrounded by a hinged friction brake element 35 asusual. A recess 36 is formed in the peripheral surface of the brakeelement 35 for receiving the outer edge of the re-inforcing web 31 onthe bracket plate 1. The brake collar 35' includes a pair of hingedlyconnected sections with their free ends yieldingly urged together bymeans of a spring and bolt connection and the inner peripheral surfaceof each of the brake sections 35 is provided with friction surfaceswhich are arranged to frictionally engage the collar 34 of the handle33.

Mounted between the pawl carrier 25 and worm 2| is a drum 4!! having anannular channelway 4| in its peripheral surface forming opposed rimflanges 42. The hub 43 of the drum 40 is provided with a set screw 44which is adapted to lock the drum 4!] on the shaft l8 (Fig. 4). A secondset screw 45 is received in a correspondingly threaded opening 46 in thehub 43 and is arranged at right angles to the set screw 44 to enable thedrum 46 to be centered and completely balanced.

Mounted on the loom side is a bracket arm 48 which has an opening 49 forreceiving a bolt 56 which extends through an opening in the loom sideand is held in place by a retaining nut 5|. The upper end of the bracket48 is angularly bent as at 52 and is spirally twisted as at 53 throughan angle slightly greater than 45 degrees to provide a flat outwardlyextending portion 54. The bracket arm is adapted to be bolted to theloom side as shown in Figure 1 at an angle of approximately 45 degreesso that the flat end portion 54 will extend in a vertical plane parallelwith the axis of the let-off drive shaft l8. Surrounding the drum 4!] isa brake collar 55 which is formed in identically the same manner as thebrake collar 35 and includes a pair of hingedly connected semi-circularsections having their free ends yieldingly connected by means of a boltextending through suitable lugs with a coil spring encircling the boltand one end abutting the end of the bolt, and the other engaging one ofthe flanges to yieldingly urge the hinged sections of the brake collar55 together. The internal surfaces of the semi-circular brake collarsections are provided with a friction element which is received betweenthe rim flanges 42 within the annular recess or groove 4|. Thus, thecollar is supported against axial movement and in order to preventrotation thereof the peripheral surface of one of the collar sections isprovided with a radial recess 56 for receiving the flat vertical end 54of the bracket 48.

In operation, the linkage 2B controlled by the lay sword (not shown)oscillates the pawl carrier 25 which imparts a corresponding motion tothe ratchet wheel 24 which drives the shaft [8. The worm 2| thus rotatesthe warp beam through the worm wheel 21 and the spur gear on the driveshaft 29. When the collars 35' and 55 are adjusted to provide thedesired friction between the collars and the drums 34 and 40, the shaft18 will be rotated under constant friction and hence, the warp beam willbe correspondingly tensioned such that the let-off will be uniform andthe quality of the cloth produced will be greatly increased andenhanced.

I claim:

1. In a loom let-off, a let-off drive shaft, ratchet mechanism forintermittently rotating said shaft on the lower end thereof, a wormsecured to the let-off drive shaft spaced above said ratchet mechanism,a drum having its hub secured to said shaft between the ratchetmechanism and said worm, a friction brake collar surrounding said drumand in yielding engagement therewith, a recess in said collar and abracket secured to the loom side having an angular end portion receivedin the recess in said collar.

2. In a loom let-off, a let-off drive shaft, ratchet mechanism forrotating said shaft on the lower end thereof, a worm secured to thelet-off drive shaft spaced above said ratchet mechanism for driving thewarp beam of the loom, a drum having its hub secured to the let-offdrive shaft and arranged between the ratchet mechanism and said worm, afriction brake collar surrounding said drum and including hingedlyconnected sections yieldingly urged together to exert friction force onsaid drum, a recess in the peripheral portion of one of the brake collarsections and a bracket affixed to the loom side having an angular upperend spirally twisted to provide a flat vertically extending detentadapted to be received in the recess in the peripheral portion of one ofthe brake collar sections.

HECTOR EMOND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date A.I.1'76 Snell et al. Oct. 6,1857 222,886 Flanagin et al Dec. 23, 1879 264,864 Crompton et al. Sept.26, 1882 266,351 Crompton et al. Oct. 24. 1882 436,724 Robinson Sept.16, 1890 2,350,954 Brown June 6, 1944

